System for controlling the duration of the time interval between blocks of data in a computer-to-computer communication system
AssigneeInternational Business Machines Corporation
InventorSiegfried W. Ulmer
Life of this patent
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Abstract
System for controlling the duration of the time interval between the blocks of data transmitted by a computer 1. A channel 7 transfers the first block to be transmitted to a control unit 2 which sends same over a line 4 through a modem 3. When the block has been transmitted, the unit 2 signals the channel accordingly and receives therefrom a command specifying the duration of the time interval between the blocks. The unit 2 activates interval timing means and signals the channel 7 when the time interval has elapsed. The channel can then send the second block to the unit 2.
Claims4
In a communication system of the type that comprises a computer connected to a transmission medium through a front-end communication unit and which transmits data blocks separated from each other by an interval, a system for controlling the duration of said interval, characterized in that it comprises:
- transfer means located in the computer for sending a first data block to the front-end unit,
- means located in the front-end unit for sending said first data block over the transmission medium,
- end means located in the front-end unit for sending to the computer a first end indication that said first data block has been transmitted,
- means located in the computer for sending to the front-end unit, in response to said first indication, a command specifying the duration of the time interval which is to separate the transmission of said first data block from that of a next data block,
- timing means located in the front-end unit, and
- means located in the front-end unit for decoding said command and activating said timing means to cause same to determine a time interval whose duration is equal to that specified by said command, said end means being caused to send to the computer a second end indication when the time interval determined by said timing means has expired, and said transfer means being responsive to said second end indication
- for sending a second data block to the front-end unit, in order that said second block may be sent over the transmission medium by said front-end unit.
In a communication system of the type that comprises a computer connected to a transmission medium through a front-end communication unit and which transmits N data blocks separated from each other by an interval, said computer including a main storage wherein the first n data blocks to be transmitted are respectively stored in n areas, with n being an integer higher than or equal to 2 and lower than N, with the remainder of said N data blocks being stored in an external storage, a system for controlling the duration of the interval between blocks, characterized in that it includes:
- transfer means located in the computer for transferring successively
- the data blocks stored in said main storage from said main storage to the front-end unit;
- means located in the front-end unit for sending the data block received from said main storage over the transmission medium;
- end means located in the front-end unit for sending to the computer
- an end indication after each of said data blocks has been transmitted
- means located in the computer responsive to the end indication sent by said end means after the first data block has been transmitted for sending to the front-end unit a command specifying the duration of the interval which is to separate the transmission of said first data block from that of a next data block,
- timing means located in the front-end unit,
- means located in the front-end unit for decoding said command and activating said timing means to cause same to determine a time interval whose duration is equal to that specified by said command, said end means being caused to send an end indication to the computer when said time interval has expired, and said transfer means being responsive to the last recited end indication for transferring a second data block from said main storage to the front-end unit;
- and
- means located in the computer for transferring the (n+1).sup.th data block from external storage to the first area of main storage, when said first data block has been transmitted by the front-end unit, the remaining ones of said N data blocks in external storage being successively transferred to the freed areas of main storage and send to the front-end unit to be transmitted in a similar manner.
Dependencies are inferred from the claim text.